LAKE LOUISE - A two-and-a-half-year-old grizzly bear left orphaned when his mother was plowed down by a train last year has made it through the busy summer months - but the fate of his sibling is not known for sure.

The young bruin, known as Bear 128, was last seen hanging out on the slopes of the Lake Louise ski hill, but he has not been traveling with another bear all summer long and had not been seen with his sibling since May.

The mother of the young grizzly bears was killed on the Canadian Pacific Railway tracks on May 28, 2011, in what was considered a blow to the regional grizzly population, which is estimated to be around 60.